This section provides background information related to the present disclosure which is not necessarily prior art.
Aqueous urea exhaust treatment fluids are used to treat engine exhaust. Because the urea solution is aqueous, the urea solution is preferably atomized by dosing module when dosing into the exhaust stream to ensure conversion of the urea in the solution to ammonia and evaporation of the water. At lower temperatures, however, it can be difficult to maintain atomization of the urea solution such that the dosed urea solution may impinge on interior walls of exhaust passage. In these cases, reaction by-products may form solid deposits on interior wall of exhaust passage that can block exhaust passage.